Adaptation and Speciation Studies at White Sands, N.M. (Image 11)

Whiptail and fence lizards are dark-colored on dark soil; however, when found on white sand they exhibit a light skin color that helps protect them from predators. It is a case of convergent evolution involving the same Mc1r gene coding for color. In the dark ancestral lizards, the gene codes for Mc1-receptors that help cells, called melanocytes, produce the melanin that makes the animal dark. In the white, sand-dwelling fence lizard, one copy of the mutation is sufficient to cause fewer Mc1-receptors to integrate into cell membranes, therefore resulting in a lighter color. In the whiptail lizards, the mutation is recessive and requires two copies of the gene. This combination does not affect the number of receptors integrated into cell membranes, but adversely affects their ability to transmit signal--arriving at the same result on the macro level: a lighter lizard.
Researchers from the lab of Erica Bree Rosenblum, an assistant professor in the Department of Environmental Science Policy and Management at the University of California, Berkeley, are studying adaptation and speciation at White Sands, and are working to understand how natural selection can lead to rapid evolutionary change.
This research was supported by National Science Foundation grant DEB 03-09327. The research is now supported by an NSF CAREER (Faculty Early Career Advancement) program award, as of 2011. For more information about this research, see the NSF press release Looks Can Be Deceiving, or visit the Rosenblum lab website.
Credit: Zina Deretsky, National Science Foundation